Emergent Excitations in Semiconducting Moiré Superlattices

Excitations in quantum systems govern their responses to intrinsic and extrinsic perturbations. Emergent excitations from the interplay between topology and correlation can drive new phase instabilities and enable novel device concepts. While a plethora of intriguing ground states are reported in two-dimensional flatband systems, it has been challenging to directly probe excitations, particularly those decoupled from the charge sector. In this talk, I will discuss our recent efforts to investigate excitations in semiconducting moiré superlattices. We developed an ultrafast imaging technique to record their complete space-time evolution, such as space-and-time-resolved transport. This allows us to simultaneously capture and separate multiple collective excitations, identify their nature, and distinguish them from conventional ones. These emergent excitations govern dynamic responses of the system and play a central role in phase stability and transition. Our results highlight new insights encoded in collective excitations and open avenues for studying and engineering correlated quantum systems through nonequilibrium approaches.

Speaker: Chenhao Jin, UC Santa Barbara